1191491840 has 324 divisors, whose sum is σ = 3672448668. Its totient is φ = 369008640.

The previous prime is 1191491831. The next prime is 1191491863. The reversal of 1191491840 is 481941911.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 388562944 + 802928896 = 19712^2 + 28336^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1191491794 and 1191491803.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 7589042 + ... + 7589198.

Almost surely, 2^1191491840 is an apocalyptic number.

1191491840 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1191491840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1836224334).

1191491840 is an abundant number, since it is smaller than the sum of its proper divisors (2480956828).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1191491840 is a wasteful number, since it uses less digits than its factorization.

1191491840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 214 (or 182 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 1191491840 is about 34517.9929891644. The cubic root of 1191491840 is about 1060.1411465065.

The spelling of 1191491840 in words is "one billion, one hundred ninety-one million, four hundred ninety-one thousand, eight hundred forty".